U.S. patent number 5,611,778 [Application Number 08/331,646] was granted by the patent office on 1997-03-18 for surgical instrument for performing epidural anesthesia.
This patent grant is currently assigned to Vygon. Invention is credited to Thierry Brinon.
United States Patent |
5,611,778 |
Brinon |
March 18, 1997 |
**Please see images for:
( Certificate of Correction ) ** |
Surgical instrument for performing epidural anesthesia
Abstract
Surgical instrument for epidural anesthesia comprising a needle
and catheter associated therewith which slides in the needle. The
catheter has a set of main axial reference marks coinciding with an
index on the needle. A reading will indicate the length of the
catheter extending from the distal end of the needle. The catheter
also includes a set of auxiliary reference marks distinguishable
from the main reference marks.
Inventors: |
Brinon; Thierry (Montsoult,
FR) |
Assignee: |
Vygon (Ecouen,
FR)
|
Family
ID: |
9429785 |
Appl.
No.: |
08/331,646 |
Filed: |
November 10, 1994 |
PCT
Filed: |
May 12, 1993 |
PCT No.: |
PCT/FR93/00465 |
371
Date: |
November 10, 1994 |
102(e)
Date: |
November 10, 1994 |
PCT
Pub. No.: |
WO93/23109 |
PCT
Pub. Date: |
November 25, 1993 |
Foreign Application Priority Data
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May 14, 1992 [FR] |
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92 05857 |
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Current U.S.
Class: |
604/117;
604/158 |
Current CPC
Class: |
A61M
25/01 (20130101); A61M 2025/0008 (20130101); A61B
2090/062 (20160201) |
Current International
Class: |
A61M
25/01 (20060101); A61B 19/00 (20060101); A61M
005/00 () |
Field of
Search: |
;604/117,158,161,164,178,280,282 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0406586 |
|
Jan 1991 |
|
EP |
|
288589 |
|
May 1953 |
|
CH |
|
9010466 |
|
Sep 1990 |
|
WO |
|
WO91/05577 |
|
May 1991 |
|
WO |
|
Primary Examiner: Rimell; Sam
Attorney, Agent or Firm: Mason, Kolehmainen, Rathburn &
Wyss
Claims
I claim:
1. A surgical instrument for performing epidural anesthesia
comprising:
a needle having an index mark defined thereon; and
an associated catheter sliding inside said needle, said catheter
having a set of main axial marks that when said catheter is
inserted in said needle, coincide with said index mark on said
needle, to indicate merely by reading and without performing any
calculations, the length of said catheter extending beyond the
distal end of said needle, said catheter further having a set of
auxiliary marks easily distinguished from said main marks that are
suitabe for indicating, merely by being read and without performing
any calculations, the length of said catheter that extends from its
distal end to each of said auxiliary marks; and
a cursor that is slidably mounted on said needle, said cursor
bearing against the edge of an incision through which said needle
is inserted and moving along said needle through a distance
corresponding to the length that said needle is inserted into said
incision.
2. A surgical instrument according to claim 1, wherein said set of
main axial marks comprises regularly spaced-apart main graduations
extending from an origin situated at a distance from the distal end
of said catheter, said distance corresponding to the distance
between the distal end of said needle and said index mark defined
thereon.
3. A surgical instrument according to claim 2, wherein said main
graduations are spaced apart at one centimeter intervals.
4. A surgical instrument according to claim 1, wherein said set of
auxiliary marks comprises regularly spaced-apart auxiliary
graduations extending from an origin that coincides with the distal
end of said catheter.
5. A surgical instrument according to claim 4, wherein said
auxiliary graduations are spaced apart at one centimeter
intervals.
6. A surgical instrument according to claim 1, wherein said main
axial marks and said auxiliary marks are disposed on the catheter
to form two scales in the vicinity of each other that facilitates
the reading thereof.
7. A surgical instrument for performing epidural anesthesia
comprising:
a needle having an index mark defined thereon; and
an associated catheter sliding inside said needle, said catheter
having a set of main axial marks that when said catheter is
inserted in said needle, coincide with said index mark on said
needle, to indicate merely by reading and without performing any
calculations, the length of said catheter extending beyond the
distal end of said needle, said catheter further having a set of
auxiliary marks easily distinguished from said main marks that are
suitable for indicating, merely by being read and without
performing any calculations, the length of said catheter that
extends from its distal end to each of said auxiliary marks,
wherein said main axial marks and said auxiliary marks are of
different colors.
8. A process of performing epidural anesthesia utilizing a needle
that has axially spaced-apart graduations suitable for indicating
directly, merely by reading and without performing any
calculations, the length of said needle extending from its distal
end to each of said graduations; that is adapted to receive a
catheter suitable for sliding inside said needle, said catheter
being provided with axial marks comprising regularly spaced-apart
graduations extending from an origin that coincides with the distal
end of said catheter and suitable for indicating, merely by being
read and without performing any calculations, the length of the
catheter that extends from its distal end to each of said marks;
and that is provided with a cursor that is slidably mounted on said
needle so as to bear against the edge of an incision through which
said needle is to be inserted, comprising the following steps:
a) inserting into a patient said needle until said needle
penetrates into the epidural space, said cursor moving along said
needle through a distance corresponding to the length of said
needle inserted into said incision, said cursor being prepositioned
at the distal end of said needle;
b) inserting said catheter into said needle and pushing said
catheter into the epidural space;
c) withdrawing said needle; and
d) subtracting the length given by the value of the graduation of
the needle indicated by said cursor from the length given by the
value of the graduation of the catheter closest of the body of the
patient, in order to determine the length of the catheter extending
inside the epidural space so as to insure that said catheter is
correctly positioned within said epidural space before anesthetic
is injected using said catheter.
Description
The present invention relates to the field of surgical instruments
comprising a needle and an associated catheter capable of sliding
inside the needle, in particular for performing epidural
anesthesia.
Epidural anesthesia is a technique that is widespread at present,
and as shown in FIG. 1 it consists in putting a catheter C into
place in the epidural space P of a patient in order to inject an
anesthetic by means of a needle A which is provided at its distal
end 5 with a tapering chamfer tip, also known as a Tuohy
needle.
To perform epidural anesthesia, the anesthetist generally begins by
inserting the needle A in the back of the patient until the distal
end 5 of the needle penetrates into the epidural space P, then the
catheter C is inserted via the proximal opening 10 of the needle
until it penetrates into the epidural space P via the distal end 5
of the needle.
In order to avoid trauma to this sensitive region of the patient,
it is important to avoid pushing the needle in too deep, and thus
to know the length of needle that has been inserted into the back
of the patient. To do this, a Tuohy needle A of the prior art is
generally provided, as shown in FIG. 2, with marks 15 that are
spaced apart axially uniformly along its length, thereby enabling
the anesthetist to deduce by calculating the length of needle that
has been inserted into the back of the patient, i.e. by knowing the
total number of marks on the needle and by subtracting therefrom
the number of marks that remain visible after the needle has been
inserted.
It is also important to know the length of catheter that has been
inserted into the epidural space, and the catheter C is generally
provided for this purpose with identical marks uniformly spaced
axially along its length. To discover the length of catheter
extending in the epidural space P, the anesthetist generally counts
the number of marks on the catheter C that go in through the
proximal opening 10 of the needle as the catheter is being pushed
into the needle and after it has left the chamfer thereof, which
the anesthetist can feel easily since it becomes more difficult to
urge the catheter into the needle once the end of the catheter has
gone beyond the distal end of the needle. Thereafter, the Tuohy
needle A is withdrawn while the catheter is left in place in the
epidural space in order to inject an anesthetic solution
therein.
The anesthetist encounters several difficulties that occur during
the various steps of performing epidural anesthesia as described
above.
Firstly, to know the lengths of needle and of catheter inserted
into the back of the patient, the surgeon must note or remember the
total numbers of graduations carried by the needle and by the
catheter, and must subtract therefrom the numbers of graduations
that remain visible after insertion of the needle or of the
catheter, and this is not easily done in the context of a surgical
operation.
Also, when the needle is being extracted, the catheter tends to be
entrained with the needle because of friction, and it then becomes
difficult to establish with accuracy the length of catheter that
remains in the epidural space after the needle has been withdrawn,
which problem is illustrated diagrammatically in FIG. 3.
Finally, since the catheter may remain in place for several hours,
there is a danger of it moving during this period and it is
important to know its position accurately before any further
injection of anesthetic.
The present invention provides a surgical instrument comprising a
needle and an associated catheter suitable for sliding inside a
needle, in particular for performing epidural anesthesia, remedying
the main difficulties described above.
This surgical instrument is characterized in that the catheter is
provided with a set of main axial marks suitable, when the catheter
is inserted in the needle, for coinciding with an index mark
defined on the needle, to indicate merely by reading and without
performing any calculation, the length of catheter extending beyond
the distal end of the needle, and is provided with a set of
auxiliary marks easily distinguished from the main marks and
suitable for indicating, merely by being read and without
performing any calculations, the length of the catheter that
extends from its distal end to each of said auxiliary marks.
The present invention also provides a needle and a catheter taken
separately and suitable for use in forming a surgical instrument of
the invention.
Other characteristics and advantages of the invention appear on
reading the following detailed description of a non-limiting
embodiment of the present invention and on examining the
accompanying drawings, in which:
FIG. 1, described above, shows the insertion of a catheter into the
epidural space of a patient;
FIG. 2 shows a needle provided with marks that are uniformly spaced
apart axially, as described above and illustrating the state of the
art;
FIG. 3, described above, illustrates the problems posed in the
prior art by withdrawing the needle from the back of the patient
while leaving the catheter in place in the epidural space;
FIG. 4 is a front view of a needle of the invention;
FIG. 5 is a side view in the plane of the front view of FIG. 4,
showing a needle of the invention together with its associated
catheter, likewise of the invention;
FIG. 6 is a bottom view of the catheter shown in FIG. 5;
FIGS. 7 to 11 show various steps in the performance of epidural
anesthesia using a surgical instrument of the invention; and
FIG. 12 shows how the length of catheter opening out into the
epidural space is calculated after the needle has been
withdrawn.
FIGS. 1 to 3 are described above to illustrate the state of the
art.
FIG. 4 shows a needle of the invention given overall reference 100,
and comprising a hollow needle body 110 suitable for being inserted
via its distal end 1100 into the back of a patient, and provided at
its opposite end 1200 with a coupling endpiece 120. As shown, the
distal end 1100 is preferably tapered in order to form a chamfer
115.
In accordance with an advantageous characteristic of the invention,
the needle 100 is provided on its body 110 with graduations 130
that are axially distributed therealong, and suitable for showing
directly, merely by being read and without performing any
calculations, the length of the needle extending from the distal
end 1100 to each of said graduations 130.
Preferably, and as shown, these graduations 130 comprise Arabic
numerals printed or engraved at one centimeter intervals from the
distal end 1100, together with spots 135, each placed halfway
between said graduations 130.
In accordance with another advantageous characteristic of the
invention, a cursor 140 is provided that is slidably mounted on the
body 110 of the needle, and that is suitable for bearing against an
incision made in the body of the patient and through which the
needle is inserted, so as to move along the body 110 of the needle
through a distance corresponding to the length of needle that has
been inserted into the said incision, in a manner that is described
in greater detail below.
FIG. 5 shows a surgical instrument of the present invention
comprising a needle 100 as described above with reference to FIG. 4
and an associated catheter given reference 200, which catheter is
suitable for sliding inside the body 110 and the endpiece 120, and
is suitable for being inserted via an opening 125 provided in the
coupling endpiece 120.
In accordance with a characteristic of the invention, the catheter
200 is provided with a set of main axial marks referenced 210
suitable, when the catheter 200 is inserted in the needle 100, for
coinciding with an index mark I that is defined on the needle to
indicate, merely by reading and without performing any
calculations, the length of catheter that extends from the distal
end 110 of the needle.
The index mark I can be positioned at various locations along the
needle 100 without going beyond the ambit of the present invention.
The plane of the opening 120 in the coupling endpiece preferably
serves as the index mark I, however, it would naturally be possible
to provide a window in the body 110 of the needle 100, optionally
fitted with a magnifying glass or other device suitable for making
it easier to read the marks on the catheter.
Preferably, in accordance with an advantageous characteristic of
the invention, this set of main axial marks 210 comprises regularly
spaced-apart main graduations extending from an origin 211 situated
at a distance D from the distal end 2100 of the catheter, where the
distance D corresponds to the distance between the distal end 1100
of the needle 100 and the index I defined thereon. As shown in FIG.
5, these main graduations are spaced apart at one centimeter
intervals and they preferably comprise Arabic numerals placed by
etching or printing once every centimeter from the origin 211, and
separated by lines or spots located halfway between them.
The catheter 200 is provided with a set of auxiliary axial marks
220 that are easily distinguished from the main marks 210 and that
are suitable for indicating, merely by being read and without
performing any calculations, the length of the catheter extending
from its distal end 2100 to each of said auxiliary marks 220, as
shown in FIG. 6. Preferably, this set of auxiliary marks 220
comprises regularly spaced-apart auxiliary graduations extending
from an origin that coincides with the distal end 2100 of the
catheter. Also preferably, these auxiliary graduations 220 are
Arabic numerals spaced apart at one centimeter intervals and
separated by lines or points placed halfway between two numerals.
The main marks and the auxiliary marks are advantageously disposed
on the catheter to form two scales in the vicinity of each other so
as to facilitate reading thereof. In a variant, the main marks and
the auxiliary marks may be disposed on diametrically opposite faces
of the catheter 200. The main marks 210 and the auxiliary marks 220
are advantageously of different colors.
The various steps of using a surgical instrument of the present
invention are described with reference to FIGS. 7 to 11.
The space between the spinous processes is initially anesthetized
using techniques that are known per se, then the needle 100 fitted
with its sliding cursor 140 prepositioned at the distal end 1100 is
inserted into the back D of the patient, the needle 100 also being
connected in sealed manner via the endpiece 120 to a syringe S to
constitute what is known to the person skilled in the art as a gas
or a liquid mandrel, depending on whether the syringe S is filled
with a gas or with a liquid. This gas or liquid mandrel technique
enables the anesthetist to tell accurately when the distal end 1100
of the needle penetrates into the epidural space P. Usually, the
anesthetist uses one hand to push the needle 100 towards the
epidural space P, while using the other hand to keep the gas or
liquid mandrel compressed until it collapses, where collapse takes
place when the needle 100 penetrates into the epidural space P, as
shown in FIGS. 7 and 8. It will also be seen from these figures
that the cursor 140 is placed on the needle 100 at a distance
L.sub.0 corresponding to the length of needle inserted into the
body of the patient.
Thereafter, as shown in FIG. 9, the syringe S is disconnected, and
the catheter 200 is inserted in the needle via the opening 125 of
the endpiece 120 which also serves as the index mark I.
The catheter is pushed along the needle until it reaches the distal
end 1100.
The anesthetist can then at any moment, and without performing any
calculations, observe the length L of catheter that has been
inserted into the epidural space P by reading the value 1 of the
main graduation 210 of the catheter that coincides substantially
within the index 125, as illustrated in FIG. 10.
In the example FIG. 10, it can be seen that L=2.5 cm since the
index I lies between the graduations 2 and 3.
After the needle 100 has been withdrawn and merely by reading the
auxiliary marks 220 on the catheter 200, the surgeon can discover
without performing any calculations the length L.sub.1 of the
catheter that extends inside the body of the patient, and can
easily deduce therefrom the length L' of the catheter 200 extending
inside the epidural space P by subtracting the length L.sub.0 given
by the value l.sub.0 of the graduation 130 of the needle 100
indicated by the cursor 140 from the length L.sub.1 given by the
value l.sub.1 of the auxiliary graduation 220 closest of the body
of the patient, as shown in FIGS. 11 and 12. In the example of
FIGS. 10, 11, and 12, the needle has been withdrawn without
entraining the catheter out from the epidural space since L=2.5 cm
and L'=L.sub.1 -L.sub.0 =6-3.5=2.5 cm=L.
Finally, a surgical instrument of the invention is particularly
simple and rapid in use and may be applied, without going beyond
the ambit of the invention, to surgical operations other than
epidural anesthesia, e.g. other local or regional anesthesias.
* * * * *